giantism vs overgrowth

giantism and overgrowth both are nouns.

Word	Noun	Adjective	Verb	Adverb
giantism	Yes	No	No	No
overgrowth	Yes	No	No	No

As nouns, giantism and overgrowth are synonyms defined as:

giantism and overgrowth: excessive size; usually caused by excessive secretion of growth hormone from the pituitary gland

Other synonyms of giantism include gigantism.

giantism (noun)	overgrowth (noun)
excessive largeness of stature	a profusion of growth on or over something else
excessive size; usually caused by excessive secretion of growth hormone from the pituitary gland	excessive size; usually caused by excessive secretion of growth hormone from the pituitary gland